kernel: _sys_getnull() (basically /dev/null)

6 files changed, 54 insertions, 4 deletions

diff --git a/src/cmd/tests/kernel/miscsyscall.c b/src/cmd/tests/kernel/miscsyscall.c
index 3cf3f2e..c7ce9e0 100644
--- a/src/cmd/tests/kernel/miscsyscall.c
+++ b/src/cmd/tests/kernel/miscsyscall.c
@@ -304,6 +304,24 @@ static void test_timer(void) {
 	}
 }
 
+static void test_getnull(void) {
+	hid_t h, h2;
+	char buf[16];
+	
+	test((h = _sys_getnull(0)) >= 0);
+	test((h2 = dup(h)));
+
+	test(_sys_read(h, buf, 16, 0) == -ENOSYS);
+	test(_sys_write(h, buf, 16, 0, 0) == -ENOSYS);
+	test(_sys_getsize(h) == -ENOSYS);
+	test(_sys_remove(h) == -ENOSYS);
+	test(_sys_fs_respond(h, buf, 16, 0) == -EBADF);
+	test(_sys_mount(h, "/asdf", 5) == -EGENERIC);
+
+	close(h);
+	close(h2);
+}
+
 void r_k_miscsyscall(void) {
 	run_test(test_await);
 	run_test(test_await2);
@@ -315,4 +333,5 @@ void r_k_miscsyscall(void) {
 	run_test(test_sleep);
 	run_test(test_badopen);
 	run_test(test_timer);
+	run_test(test_getnull);
 }
diff --git a/src/kernel/handle.h b/src/kernel/handle.h
index 21b4364..d502d5d 100644
--- a/src/kernel/handle.h
+++ b/src/kernel/handle.h
@@ -10,6 +10,7 @@ enum handle_type {
 	HANDLE_PIPE,
 	HANDLE_FS_FRONT,
 	HANDLE_FS_REQ,
+	HANDLE_NULL,
 };
 
 struct Handle {
diff --git a/src/kernel/syscalls.c b/src/kernel/syscalls.c
index e449953..5f53ccb 100644
--- a/src/kernel/syscalls.c
+++ b/src/kernel/syscalls.c
@@ -166,7 +166,13 @@ static long simple_vfsop(
 		|| vfsop == VFSOP_WRITE
 		|| vfsop == VFSOP_GETSIZE);
 	Handle *h = proc_handle_get(proc_cur, hid);
-	if (!h) SYSCALL_RETURN(-EBADF);
+	if (!h) {
+		SYSCALL_RETURN(-EBADF);
+	}
+	if (h->type != HANDLE_FILE && h->type != HANDLE_PIPE) {
+		SYSCALL_RETURN(-ENOSYS);
+	}
+
 	// TODO those checks really need some comprehensive tests
 	if (vfsop == VFSOP_READ && !h->readable)
 		SYSCALL_RETURN(-EACCES);
@@ -196,7 +202,9 @@ static long simple_vfsop(
 			/* already checked if this is the correct pipe end */
 			pipe_joinqueue(h, proc_cur, buf, len);
 		} else SYSCALL_RETURN(-ENOSYS);
-	} else SYSCALL_RETURN(-ENOSYS);
+	} else {
+		panic_invalid_state();
+	}
 	return 0;
 }
 
@@ -436,6 +444,15 @@ uint64_t _sys_time(int flags) {
 	SYSCALL_RETURN(now - proc_cur->basetime);
 }
 
+hid_t _sys_getnull(int flags) {
+	if (flags != 0) {
+		SYSCALL_RETURN(-ENOSYS);
+	}
+
+	hid_t hid = proc_handle_init(proc_cur, HANDLE_NULL, NULL);
+	SYSCALL_RETURN((0 <= hid) ? hid : -EMFILE);
+}
+
 long _sys_execbuf(void __user *ubuf, size_t len) {
 	if (len == 0) SYSCALL_RETURN(0);
 	if (len > EXECBUF_MAX_LEN)
@@ -491,6 +508,7 @@ long _syscall(long num, long a, long b, long c, long d, long e) {
 		break; case _SYS_WAIT2:	_sys_wait2(a, b, (userptr_t)c);
 		break; case _SYS_GETPROCFS:	_sys_getprocfs(a);
 		break; case _SYS_TIME:	_sys_time(a);
+		break; case _SYS_GETNULL:	_sys_getnull(a);
 		break; case _SYS_EXECBUF:	_sys_execbuf((userptr_t)a, b);
 		break; case _SYS_DEBUG_KLOG:	_sys_debug_klog((userptr_t)a, b);
 		break;
diff --git a/src/libc/socket.c b/src/libc/socket.c
index a8871a3..5ea7266 100644
--- a/src/libc/socket.c
+++ b/src/libc/socket.c
@@ -1,5 +1,6 @@
 #include <arpa/inet.h>
 #include <camellia.h>
+#include <camellia/syscalls.h>
 #include <errno.h>
 #include <netdb.h>
 #include <netinet/in.h>
@@ -10,8 +11,12 @@ int socket(int domain, int type, int protocol) {
 	if (domain != AF_INET || type != SOCK_STREAM || protocol != IPPROTO_TCP) {
 		return errno = ENOSYS, -1;
 	}
-	// TODO! /dev/null
-	return dup(1); // yolo
+	int h = _sys_getnull(0);
+	if (h < 0) {
+		return errno = -h, -1;
+	} else {
+		return h;
+	}
 }
 
 int bind(int, const struct sockaddr *, socklen_t) {
diff --git a/src/libc/syscall.c b/src/libc/syscall.c
index 8142028..f44c775 100644
--- a/src/libc/syscall.c
+++ b/src/libc/syscall.c
@@ -94,6 +94,10 @@ uint64_t _sys_time(int flags) {
 	return (uint64_t)_syscall(_SYS_TIME, (long)flags, 0, 0, 0, 0);
 }
 
+hid_t _sys_getnull(int flags) {
+	return (hid_t)_syscall(_SYS_GETNULL, (long)flags, 0, 0, 0, 0);
+}
+
 long _sys_execbuf(void __user *buf, size_t len) {
 	return _syscall(_SYS_EXECBUF, (long)buf, (long)len, 0, 0, 0);
 }
diff --git a/src/libk/include/camellia/syscalls.h b/src/libk/include/camellia/syscalls.h
index 6d9286b..3e7576e 100644
--- a/src/libk/include/camellia/syscalls.h
+++ b/src/libk/include/camellia/syscalls.h
@@ -22,6 +22,7 @@
 #define _SYS_WAIT2 21
 #define _SYS_GETPROCFS 22
 #define _SYS_TIME 23
+#define _SYS_GETNULL 24
 
 #define _SYS_EXECBUF 100
 #define _SYS_DEBUG_KLOG 101
@@ -86,6 +87,8 @@ hid_t _sys_getprocfs(int flags);
 /** Returns the time in nanoseconds since the first _sys_time call in the process */
 uint64_t _sys_time(int flags);
 
+hid_t _sys_getnull(int flags);
+
 /* see shared/execbuf.h */
 long _sys_execbuf(void __user *buf, size_t len);